Earth's Crust in Motion

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Vocabulary

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earthquake-the shaking of the Earth
stress-force that changes a rock's formation
shearing-stress that sends giant chunks of rock in opposite paths
tension-stress that stretches rock so much that it causes the middle to become skinnier than before.
compression-stress that pushes rock together until it folds or cracks
deformation-physical change in the Earth's crust
fault- crack in the Earth's crust where mounds of rock pass each other
strike-slip fault-type of fault where rock on either side move past each other sideways with an up-or-down motion
normal fault-the Hanging wall is faced downward, while the footwall is upward
reverse fault-type of fault where the hanging wall comes upward
hanging wall-upper half of fault
footwall-forms lower half of fault
fold-caused by bends in the part of Earth's crust when compression pushes the rock together
anticline-causes the rock to bend upward,forming an arch
syncline-a fold at the bottom of the rock,creating a "U" shaped structure
plateau-flat land that is located high above sea level

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Outline

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Stress in the crust

• Earthquake
  • shaking and trembling of the earth's surface
• stress
  • force that changes rock's formation

Types of Stress

• Shearing
  • causes rock to break or change formation
• Tension
  • makes rock thin in the middle by stretching the rock
• Compression
  • squeezes rock together until it folds or breaks
• Deformation
  • change in volume or shape of the earth's crust

Kinds of Faults

• shearing causes strike-slip faults
  • Strike-Slip Faults
    • fault where both sides of rock slip past each other with an up/down motion
• tension causes normal faults
  • Normal Faults
    • fault where the hanging wall lies above the footwall
      • fault is at an angle
• compression causes reverse faults
  • Reverse Fault
    • fault where footwall lies above the hanging wall

Friction Along Faults

• friction
  • friction is a force that opposes one rock as it moves on another

Mountain building

• plate movement can build up Earth's surface
• Mountain Formed by Faulting
  • Fault Block Mountain
  • tension force makes lots of normal faults
    • when two normal faults are parallel,one block is in between
      • when block in between slides upward, a valley forms
• Mountains Formed by Folding
  • Sometimes,plate movement causes crust to fold
    • when compression stresses rock,it can cause folding of the crust
• Antyclines and Synclines
  • when compression has folded the rock,anticlines and synclines can be revealed
• Plateaus
  • some are formed when verticle faults push up a flat block of rock
    • has lots of different layers,contains more width than height due to layers

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